Circulating pump



Oct. 24, 1961 P. AKERMANN CIRCULATING PUMP 2 Sheets-Sheet 1 Filed Nov. 12, 1958 Fig. I

INVENTOR. Pau/ AKE/FDUJW? BY E M xgl/L bl ATTo mueass United States Patent 3,005,415 CIRCULATING PUMP Paul Akerinann, Birsfelden, Switzerland, assignor to E.M;B. Elektromotorenbau A.G., Birsfelden, Switzerland, a company of Switzerland Filed Nov. 12, 1958, Ser. No. 773,205 3 Claims. ((1103-87) The present invention relates to a pump-and-moto-r assembly of a circulating pump for central heating and more particularly to an assembly of such a pump and an electric motor in which the housing is in two separable portions enclosing-pump and'motor and including-a spiral housing portion and a cover portion.

It is an object of the present invention to provide for a pump-and-motor assembly of this type facilitating assembly and disassembly operations so as to permit overhauling of pump and motor in a simple manner.

Another object of the present invention is to provide for the improved supporting of the common shaft for rotor and impeller in a pump-and-motor assembly which will avoid axialforces'acting on the shaft from becoming effective at the bearings thereof.

Still another object of the present invention is the provision of a pump-and-motor assembly for the circulation of heating medium in central heating systems which is of simple and sturdy construction and avoids excessive wear.

These and other objects of the present invention will become better apparent from the following description when taken in conjunction with the accompanying drawing in which:

FIG. 1 shows in axial vertical section a pump-andmotor assembly of circulating pump embodying the invention;

FIG. 2 shows the assembly of FIG. 1 in axial horizontal section.

Generally it will be seen that the present invention provides for a pump-and-motor assembly in which the housing is so divided that the stator ring extends into the pump or spiral housing portion as well as into the cover housing portion, both housing portions being maintained in co- ;axial relation by the stator ring. Moreover the pump Wheel or impeller presents a smaller diameter than the rotor of the electric motor, and screws provided with lefthand and right-hand thread are used to interconnect the two housing portions.

Referring now more particularly to the drawing, it will be seen that the housing consists of the portions A and B. The spiral housing portion A is formed with an inlet or supply channel 1 and with an outlet or discharge channel 2. It will be understood that the inlet channel 1 communicates with outlet 2 over the spiral casing 8a formed by a hub 8. Also accommodated in this section are a bearing bush 3 and the terminals 4- for the stator permitting the connection of the latter with a source of current not shown. The cover portion B is provided with a hub 5 of cylindrical form and extending inwardly, in which a bearing bush 6 and a cover screw 7 are arranged, the latter serving to check the direction of rotation of the motor. The outside surface of the hub '5 and that of the hub S of the housing portion A serve to support a cylindrical tube 9 over sealing rings 10. Chambers 11 and 12 are formed by the tube 9 and hubs 5 and 8 of the two housing portions. Chamber 11 communicates with the spiral casing and consequently is'filled with pump fluid in which the rotor rotates, While chamber 12 containing the stator 13 is sealed therefrom. The stator 13 is supported in a ring 14 seated in the housing portion A. A rotor shaft 15 is journalled in the bearing bushes 3 and 6; it carries the rotor 16 and the impeller 17 which latter is arranged in the spiral housing. The impeller 17 is smaller ice r in diameter than the rotor 16 to permit insertionof a unit formed by rotor, impeller and shaft into the housing portion A. The two housing portions are so designed that the stator ring 14 extends both into the portion A and the portion B. These portions are thus centered by the stator ring 14 and are interconnected by screws 18. These screws 18 are preferably provided with portions having left-hand and right-hand threads, so that when the housing is opened by rotating the screws 18, thehousing portion B is separated from the housing portion A and held in that position to preve'ntthe split tube *9 from suddenly slipping off its sealing rings 10. v

The rotor shaft is provided with a bore 20 which permits passage of pressure medium therethrough so as to prevent the pressure medium arriving behind one of the bearing bushes 3 and 6 from exerting a one-sided axial pressure on flie rotor shaft 15 which would result in excessive wear in the bearings. Due to the bore 20 the fluid pressure will act equally on both ends of shaft 15, 'so that the resulting forces will tend to compensate each other and prevent axial forces from becoming effective to displace the shaft in one direction.

Various changes and modifications may be made without departing from the spirit and scope of the present invention and it is intended that such obvious changes and modifications be embraced by the annexed claims.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

1. A pump-and-motor assembly including a liquid circulating pump and an electric motor driving said pump; said assembly comprising a housing having two separable portions, each housing portion including internally thereof a shaft bearing and an annular inwardly directed hub, a shaft having two ends supported in said shaft bearings, said shaft having a longitudinal bore interconnecting the ends thereof, one of said housing portions forming a spiral casing, a pump impeller seated on said shaft and located within said spiral casing, an annular tubular member sealingly connected to said hub of said one housing portion and extending into sealing relation with said hub of the other of said housing portions, said tubular member forming an inner cylindrical chamber and an outer annular chamber in said housing in coaxial relation with said shaft, said cylindrical inner chamber communicating with said spiral casing and being adapted to be supplied with liquid from said pump impeller, a rotor seated on said shaft for rotation therewith within said inner chamber, an annular stator within said outer annular chamber and surrounding said rotor, said stator extending into both of said housing portions and centering the latter in coaxial relation with respect to each other, said annular tubular member having end portions and disposed in overlying relationship with respect to said respective hubs of said housing portions and extending a distance substantially greater than the width of said rotor and adjacent thereto, the end portions of said tubular member being disposed remote from said rotor, and means releasably interconnecting said housing portions with each other, said rotor having a diameter larger than said pump impeller to permit removal of said shaft with said pump impeller from said spiral casing through said tubular member when said housing portions are released by said interconnecting means.

2. A pump-and-rnotor assembly including a liquid circulating pump and an electric motor driving said pump; said assembly comprising a housing having two separable portions, each housing portion including internally thereof a shaft bearing and an annular inwardly directed hub, a shaft having two ends supported in said shaft bearings, said shaft having a longitudinal bore interconnecting the ends thereof, one of said housing portions forming a spiral casing, a pump impeller seated on said shaft and located within said spiral casing, an annular tubular member sealingly connected in overlying relationship to said hub of said one housing portion and said hub of the other of said housing portions, said annular tubular member defining an inner cylindrical chamber and an outer annular chamber in said housing in coaxial relation with said shaft, said cylindrical inner chamber communicating with said spiral casing and being adapted to be supplied with liquid from said pump impeller, a rotor seated on said shaft for rotation therewith within said inner chamber and axially spaced from said pump impeller, an annular stator within said outer annular chamber and surrounding said rotor, said stator extending into both of said housing portions and center ing the latter in coaxial relation with respect to each other, said annular tubular member having end portions and radially spaced from said rotor, said tubular member overlying said rotor in an axial direction and having a length substantially greater than the width of said rotor with said end portions thereof disposed remote from said rotor to effectively seal said stator from said liquid when contained within said cylindrical inner chamber, and screw means releasably interconnecting said housing portions with each other, said rotor having a diameter larger than said pump impeller to permit removal of said shaft with said impeller from said spiral casing through said tubular member when said housing portions are released by said screw means.

3. An assembly according to claim 2, wherein said screw means have two thread portions, one of said thread portions being threaded in left-hand direction and the other of said thread portions being threaded in righthand direction, each one of said thread portions of said screws engaging a correspondingly threaded bore in each of said housing portions to permit displacement of the latter toward and away from each other by the rotation of said screws.

References titted in the file of this patent UNITED STATES PATENTS 2,517,233 Peters Aug. 1, 1950 2,535,695 Pezzillo Dec. 26, 1950 2,669,187 Guyer Feb. 16, 1954 2,763,214 White Sept. 18, 1956 2,766,695 Gailloud Oct. 16, 1956 2,875,694 Carter Mar. 3, 1959 FOREIGN PATENTS 85,446 Norway Feb. 26, 1955 1,040,376 Germany Oct. 2, 1958 

